I’m not a big expert on database technology, but I am aware of there being at least a few database systems (“In-Memory”) that use the RAM of the computer for transient storage, and since RAM doesn’t use files as a concept in the same way, the data stored there isn’t exactly inside a “file,” so to speak.
That said, they are absolutely dwarfed by the majority of databases, which use some kind of file as a means to store the database, or the contents within it.
Obviously, that’s not to say using files is bad in any way, but the possibilities for how database software could have developed, had we not used files as a core computing concept during their inception, are now closed off. We simply don’t know what databases could have looked like, because of “lock-in.”
I understand why people seem to think we should tolerate these views, because “muh free speech,” but to them, I say: